While it's common knowledge that man's best friend has four paws, a wet nose and a penchant for playing fetch, did you also know that the role of dogs on the front line (1914-1918) was of grave - sometimes pivotal - importance?

Life was certainly no walk in the park for the estimated 20,000 dogs who contributed to the British war effort, whether they were carrying aid to the wounded, accompanying patrols to sniff out the enemy or helping to pull along heavy equipment. They were so important, in fact, that in the early months of 1917 the War Office created the War Dog School Of Instruction in Hampshire in a bid to hone their skills yet further.

“A watchdog never barks; at the most he will use a low growl to indicate the presence or approach of a hostile force," states the Dundee Evening Telegraph, in a 1916 report we came across in our British newspaper collection, “More often than not the mere pricking of the ears or the attitude of expectancy is sufficient to put his master on his guard."

More interesting still, is the fact that although some of these canine heroes were rescued from lives as strays, many thousands of families actually made the heart-wrenching decision to say goodbye to their much-loved family pets, donating them to the war effort so they could serve their country on the front line. Perhaps one of them was even donated by your own family.

Four-legged fighters: A few key facts

Sentry dogs, usually Dobermans, were trained to patrol alongside their designated guard, and give a warning such as a growl when they sensed an unknown or threatening intrusion to the area.

Scout dogs, who worked with soldiers patrolling terrain on foot, were subtler still. Able to smell an enemy up to a kilometre away, they simply raised their shackles and pointed their tail to signify danger. This helped the squad to travel undetected.

Messenger dogs were an astonishing aid to communications during World War One. Trench warfare meant that crucial messages were easily lost. Both human runners and vehicles were large targets for snipers, and travel by road could be virtually impossible, yet highly-trained, speedy messenger dogs often succeeded where all other resorts failed.

Casualty or 'Mercy' dogs performed a vital, yet tragic service during World War One. Carrying packs of medical supplies, these dogs were sent into the battlefield where they would seek out the wounded and dying. Some men were able to use these supplies to treat their own wounds. The more seriously injured simply sought the animal's comfort as they lay dying.